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Bolton SJ, Adriani A, Adumitroaie V, Allison M, Anderson J, Atreya S, Bloxham J, Brown S, Connerney JEP, DeJong E, Folkner W, Gautier D, Grassi D, Gulkis S, Guillot T, Hansen C, Hubbard WB, Iess L, Ingersoll A, Janssen M, Jorgensen J, Kaspi Y, Levin SM, Li C, Lunine J, Miguel Y, Mura A, Orton G, Owen T, Ravine M, Smith E, Steffes P, Stone E, Stevenson D, Thorne R, Waite J, Durante D, Ebert RW, Greathouse TK, Hue V, Parisi M, Szalay JR, Wilson R. Jupiter's interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft. Science 2018; 356:821-825. [PMID: 28546206 DOI: 10.1126/science.aal2108] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 05/01/2017] [Indexed: 11/02/2022]
Abstract
On 27 August 2016, the Juno spacecraft acquired science observations of Jupiter, passing less than 5000 kilometers above the equatorial cloud tops. Images of Jupiter's poles show a chaotic scene, unlike Saturn's poles. Microwave sounding reveals weather features at pressures deeper than 100 bars, dominated by an ammonia-rich, narrow low-latitude plume resembling a deeper, wider version of Earth's Hadley cell. Near-infrared mapping reveals the relative humidity within prominent downwelling regions. Juno's measured gravity field differs substantially from the last available estimate and is one order of magnitude more precise. This has implications for the distribution of heavy elements in the interior, including the existence and mass of Jupiter's core. The observed magnetic field exhibits smaller spatial variations than expected, indicative of a rich harmonic content.
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Affiliation(s)
- S J Bolton
- Southwest Research Institute, San Antonio, TX 78238, USA.
| | - A Adriani
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, 00133 Rome, Italy
| | - V Adumitroaie
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - M Allison
- Goddard Institute for Space Studies, New York, NY 10025, USA
| | - J Anderson
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - S Atreya
- University of Michigan, Ann Arbor, MI 48109, USA
| | - J Bloxham
- Harvard University, Cambridge, MA 02138, USA
| | - S Brown
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - J E P Connerney
- Space Research Corporation, Annapolis, MD 21403, USA.,NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - E DeJong
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - W Folkner
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - D Gautier
- Laboratoire d'Études Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, 92195 Meudon, France
| | - D Grassi
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, 00133 Rome, Italy
| | - S Gulkis
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - T Guillot
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Laboratoire Lagrange CNRS, 06304 Nice, France
| | - C Hansen
- Planetary Science Institute, Tucson, AZ 85719, USA
| | - W B Hubbard
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
| | - L Iess
- Sapienza University of Rome, 00185 Rome, Italy
| | - A Ingersoll
- California Institute of Technology, Pasadena, CA 91125, USA
| | - M Janssen
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - J Jorgensen
- National Space Institute, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Y Kaspi
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - S M Levin
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - C Li
- California Institute of Technology, Pasadena, CA 91125, USA
| | - J Lunine
- Cornell University, Ithaca, NY 14853, USA
| | - Y Miguel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, Laboratoire Lagrange CNRS, 06304 Nice, France
| | - A Mura
- Institute for Space Astrophysics and Planetology, National Institute for Astrophysics, 00133 Rome, Italy
| | - G Orton
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - T Owen
- Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - M Ravine
- Malin Space Science Systems, San Diego, CA 92121, USA
| | - E Smith
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - P Steffes
- Center for Space Technology and Research, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - E Stone
- California Institute of Technology, Pasadena, CA 91125, USA
| | - D Stevenson
- California Institute of Technology, Pasadena, CA 91125, USA
| | - R Thorne
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA 90095, USA
| | - J Waite
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - D Durante
- Sapienza University of Rome, 00185 Rome, Italy
| | - R W Ebert
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - T K Greathouse
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - V Hue
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - M Parisi
- Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA
| | - J R Szalay
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - R Wilson
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA
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Tyler GL, Sweetnam DN, Anderson JD, Campbell JK, Eshleman VR, Hinson DP, Levy GS, Lindal GF, Marouf EA, Simpson RA. Voyager 2 radio science observations of the uranian system: atmosphere, rings, and satellites. Science 2010; 233:79-84. [PMID: 17812893 DOI: 10.1126/science.233.4759.79] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Voyager 2 radio occultation measurements of the Uranian atmosphere were obtained between 2 and 7 degrees south latitude. Initial atmospheric temperature profiles extend from pressures of 10 to 900 millibars over a height range of about 100 kilometers. Comparison of radio and infrared results yields mole fractions near the tropopause of 0.85 and 0.15 +/- 0.05 for molecular hydrogen and helium, respectively, if no other components are present; for this composition the tropopause is at about 52 kelvins and 110 millibars. Distinctive features in the signal intensity measurements for pressures above 900 millibars strongly favor model atmospheres that include a cloud deck of methane ice. Modeling of the intensity measurements for the cloud region and below indicates that the cloud base is near 1,300 millibars and 81 kelvins and yields an initial methane mole fraction of about 0.02 for the deep atmosphere. Scintillations in signal intensity indicate small-scale stucture throughout the stratosphere and upper troposphere. As judged from data obtained during occultation ingress, the ionosphere consists of a multilayer structure that includes two distinct layers at 2,000 and 3,500 kilometers above the 100-millibar level and an extended topside that may reach altitudes of 10,000 kilometers or more. Occultation measurements of the nine previously known rings at wavelengths of 3.6 and 13 centimeters show characteristic values of optical depth between about 0.8 and 8; the maxim value occurs in the outer region of the in ring, near its periapsis. Forward-scattered signals from this ring have properties that differ from those of any of Saturn's rings, and they are inconsistent with a discrete scattering object or local (three-dimensional) assemblies of orbiting objects. These signals suggest a new kdnd of planetary ring feature characterized by highly ordered cylindrical substructures of radial scale on the order of meters and azimuthal scale of kilometers or more. From radio data alone the mass of the Uranian system is GM(sys) = 5,794,547- 60 cubic kilometers per square second; from a combination of radio and optical navigation data the mass of Uranus alone is GM(u) = 5,793,939+/- 60 cubic kilometers per square second. From all available Voyager data, induding imaging radii, the mean uncompressed density of the five major satellites is 1.40+/- 0.07 grams per cubic centimeter; this value is consistent with a solar mix of material and apparently rules out a cometary origin of the satellites.
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Tyler GL, Sweetnam DN, Anderson JD, Borutzki SE, Campbell JK, Eshleman VR, Gresh DL, Gurrola EM, Hinson DP, Kawashima N, Kursinski ER, Levy GS, Lindal GF, Lyons JR, Marouf EA, Rosen PA, Simpson RA, Wood GE. Voyager Radio Science Observations of Neptune and Triton. Science 1989; 246:1466-73. [PMID: 17756001 DOI: 10.1126/science.246.4936.1466] [Citation(s) in RCA: 252] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Voyager 2 encounter with the Neptune system included radio science investigations of the masses and densities of Neptune and Triton, the low-order gravitational harmonics of Neptune, the vertical structures of the atmospheres and ionospheres of Neptune and Triton, the composition of the atmosphere of Neptune, and characteristics of ring material. Demanding experimental requirements were met successfully, and study of the large store of collected data has begun. The initial search of the data revealed no detectable effects of ring material with optical depth tau [unknown] 0.01. Preliminary representative results include the following: 1.0243 x 10(26) and 2.141 x 10(22) kilograms for the masses of Neptune and Triton; 1640 and 2054 kilograms per cubic meter for their respective densities; 1355 +/- 7 kilometers, provisionally, for the radius of Triton; and J(2) = 3411 +/- 10(x 10(-6)) and J(4) = -26(+12)(-20)(x10(-6)) for Neptune's gravity field (J>(2) and J(4) are harmonic coefficients of the gravity field). The equatorial and polar radii of Neptune are 24,764 +/- 20 and 24,340 +/- 30 kllometers, respectively, at the 10(5)-pascal (1 bar) pressure level. Neptune's atmosphere was probed to a pressure level of about 5 x 10(5) pascals, and effects of a methane cloud region and probable ammonia absorption below the cloud are evident in the data. Results for the mixing ratios of helium and ammonia are still being investigated; the methane abundance below the clouds is at least 1 percent by volume. Derived temperature-pressure profiles to 1.2 x 10(5) pascals and 78 kelvins (K) show a lapse rate corresponding to "frozen" equilibrium of the para- and ortho-hydrogen states. Neptune's ionosphere exhibits an extended topside at a temperature of 950 +/- 160 K if H(+) is the dominant ion, and narrow ionization layers of the type previously seen at the other three giant planets. Triton has a dense ionosphere with a peak electron concentration of 46 x 10(9) per cubic meter at an altitude of 340 kilometers measured during occultation egress. Its topside plasma temperature is about 80 +/- 16 K if N(2)(+) is the principal ion. The tenuous neutral atmosphere of Triton produced distinct signatures in the occultation data; however, the accuracy of the measurements is limited by uncertainties in the frequency of the spacecraft reference oscillator. Preliminary values for the surface pressure of 1.6 +/- 0.3 pascals and an equivalent isothermal temperature of 48 +/- 5 K are suggested, on the assumption that molecular nitrogen dominates the atmosphere. The radio data may be showing the effects of a thermal inversion near the surface; this and other evidence imply that the Triton atmosphere is controlled by vapor-pressure equilibrium with surface ices, at a temperature of 38 K and a methane mixing ratio of about 10(-4).
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